for National Geographic News
Salmon parents have created offspring that are 100 percent trout—the first time that a surrogate animal has produced a different species, researchers say.
Researchers took reproductive cells known as germ cells from rainbow trout and implanted them into masu salmon embryos.
The salmon served as hosts—or surrogates—for eggs and sperm made of trout genetic material.
When the adult salmons' egg and sperm were combined via artificial insemination, they produced babies that were fully trout.
Although neither trout nor salmon species is endangered, "this is a novel method for conservation of endangered species in salmon," said lead researcher Goro Yoshizaki of Tokyo University of Marine Science and Technology.
The new work offers hope that the technique could eventually produce other species that are difficult to breed, endangered, or even extinct using host species that are abundant or easily bred in captivity.
Yoshizaki and colleagues report their findings in this week's issue of the journal Science.
Trout and salmon are both part of the same family, the Salmonidae.
In recent decades many salmonids have seen their wild populations plummet, with some species becoming extinct or endangered.
Preserving these species is difficult because viable fish eggs are too large and have too high of a fat content to survive being frozen.
"So we thought freezing progenitor cells of egg and sperm will be a good alternative for egg cryopreservation," Yoshizaki said.
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